As known, computers such as desktop computers (e.g., personal computers) or notebook computers are essential tools in our daily lives. Moreover, keyboards are important input devices of computers. Via the keyboards, users can input characters or perform control operations. Generally, a keyboard comprises plural key structures. These key structures are located at specified positions. Moreover, many electronic devices or electrical operation devices are equipped with key structures that are used as operation interfaces of performing various designated functions.
For allowing users to perform the input and control operations, the key structures of the keyboard are specially designed. That is, the key structure is returned to its original position in response to a single pressing action, and a triggering signal is generated in response to the pressing action. Due to the compressible restoring mechanism of the key structure, the tactile feel of successfully pressing the key structure for the user is enhanced. In addition, the same key structure can be used to provide the next pressing action.
As for the conventional keyboards, the key structures are classified according to the types of the switches in the key structures. For example, the key structures are classified into some types, including mechanical key structures, membrane key structures, conductive rubber key structures and contactless electrostatic capacitive key structures. Generally, the use lives, the tactile feels and the fabricating cost for different types of key structures are usually different.
Moreover, the key structure is usually equipped with a scissors-type connecting element under the keycap. Due to the scissors-type connecting element, the pressing force can be effectively and uniformly distributed. In addition, the key structure further comprises an elastic element (e.g., a spring or a rubber-dome elastic element). Due to the elastic element, the scissors-type connecting element can be returned to its original position. Consequently, the key structure can be operated repeatedly. If the key structure is only equipped with the elastic element as the restoring mechanism but not equipped with the scissors-type connecting element, the distribution of the pressing force is usually not uniform. Under this circumstance, it is difficult to build the larger-area keycap of the key structure of the keyboard. For example, the key structure with the larger-area keycap includes the “Space” key, the “Enter” key, the “Shift” key, the “Caps Lock” key or any other similar multiple key.
On the other hand, the longer key structure or the larger-sized key structure is equipped with a stabilizer bar that cooperates with the scissors-type connecting element. The stabilizer bar is an elongated shaft. In addition, the stabilizer bar is located under the keycap and arranged around the scissors-type connecting element. As the overlying keycap is depressed, the stabilizer bar allows the overall keycap to be evenly moved downwardly. Consequently, the keycap is not tilted. That is, while the keycap is depressed, one side of the keycap is not higher than another side of the keycap.
In FIGS. 1A and 1B, the cross-sectional view of a key structure 10 is shown. FIG. 1A is a schematic cross-sectional view illustrating a portion of a conventional key structure, in which the key structure is in a non-depressed state. FIG. 1B is a schematic cross-sectional view illustrating a portion of the conventional key structure, in which the key structure is in a depressed state. The key structure 10 comprises a keycap 11, a stabilizer bar 13, a hook part 15, a supporting plate 12 and a pressing post 17. The hook part 15 is located under the keycap 11. The stabilizer bar 13 is pivotally coupled to the hook part 15. The key structure 10 has a recess 14 corresponding to the hook part 15. When the keycap 11 is moved downwardly, the hook part 15 is accommodated within the recess 14. The pressing post 17 is located under the keycap 11 and aligned with a key seat 16. An elastic element and a key switch (not shown) are disposed within the key seat 16. While the keycap 11 is moved downwardly, the pressing post 17 is correspondingly descended to trigger the key switch. Moreover, the pressing post 17 is returned to its original position in response to the elastic force of the elastic element.
However, since most of the above components are made of harder materials, some drawbacks occur. For example, while the keycap of the keyboard is depressed to perform a control operation or input a character, the collisions between these components may generate noise or sound. For example, as shown in FIG. 1B, the contact, the withstanding action or the collision between a bottom surface 110 of the keycap 11 and the key seat 16, between the hook part 15 and the recess 14 or between a protrusion edge 111 of the keycap 11 and the supporting plate 12 may generate noise or sound. If the keyboard device is used in the environment requiring silence (e.g., a library or an office), the generated noise may influence other people and disturbs and inconveniences the user and other people. Moreover, the collision between components may abrade the components, and thus the key structure has a malfunction.
Therefore, there is a need of providing an improved silent keyboard and an improved key structure in order to overcome the drawbacks of the conventional technologies.